randomized controlled trial of custom foot orthoses for chronic forefoot pain

Conditions: Metatarsalgia

Summary: chronic metatarsalgia (cm) causes significant pain and disability, affecting quality of life. foot orthoses (fos) including medially wedged designs with a metatarsal pad decrease excessive plantar pressure under the metatarsal heads, which is a known risk factor for developing cm. this fos model may be effective in diminishing pain and improving function in these individuals. thus, the objective of this trial is to compare the effects of medially wedged fos with a metatarsal pad and sham fos on pain and foot function in individuals with cm. this participant- and assessor-blinded superiority randomized controlled trial (rct) with two parallel groups will be conducted in trois-rivières, canada. seventy-two participants with chronic metatarsalgia (cm) will be recruited from the université du québec à trois-rivières outpatient podiatry clinic and via social media invitations. the participants will be randomized into intervention (customized fos) or control (sham fos) groups and will be evaluated at baseline and after 6 and 12 weeks, for a total duration of participation of 4 to 5 months (from the first contact until the last data collection). the primary outcomes will be: (1) "pain" subscale of the foot function index and (2) mean pain during walking for the most painful foot during the past week. the secondary outcomes will be: (1) global rating of change, (2) the 5-level eq-5d (health-related quality of life) and (3) foot function index (disability and activity limitation subscales). the medially wedged fos with a metatarsal pad are expected to provide a greater reduction in pain and improvement in foot function compared to the sham fos. this trial will help guide fos prescription recommendations for managing foot pain in individuals with cm in the future.

foot musculoskeletal disorders cause significant impairments and disabilities for those affected. among the various types of foot pain, chronic metatarsalgia (cm) is the most prevalent. metatarsalgia represents 88% of all causes of foot pain, with a prevalence of 13 to 36% in adults. it is characterized by persistent pain to one or more metatarsophalangeal joints, resulting from harm (whether of mechanical origin or not) to the anatomical structures associated with the joint, including bone, cartilage, capsule and ligaments, tendons, bursae and subcutaneous tissue, and skin. chronic metatarsalgia significantly reduces the quality of life of those affected, physically, psychologically, and socially. different treatment modalities are used for cm, such as stretching exercises, footwear modifications, and foot orthoses (fos). the first-line treatment is conservative, and surgery should be considered only when conservative treatment fails. nevertheless, there is little high-level evidence (level i) to support the efficacy of conservative treatments for cm. the reduction of the mechanical overload under the metatarsal heads during locomotion is a fundamental aspect of cm treatment, and it strongly correlates with pain reduction. foot orthoses are commonly used devices to reduce pain and improve function in individuals with musculoskeletal disorders. they reduce forefoot plantar pressure during locomotion in individuals with cm and redistribute plantar pressure more evenly. metatarsal pads, a common fos modification, effectively redistribute forefoot plantar pressure and thus reduce pain caused by excessive metatarsal loads. adding a medial wedge to fos (inclination in the frontal plane) further reduces forefoot peak pressure in healthy adults. while fos tested so far are generally effective in managing cm, their effects can be inconsistent across patients, some patients did not find them effective. from a biomechanical standpoint, fos reduce mechanical overload; however, it is crucial to determine whether they also effectively reduce pain and improve foot function. randomized controlled trials (rct) are considered the gold standard for evaluating treatment effectiveness and efficiently translating research findings into clinical practice. this study design will allow us to assess whether, in addition to their biomechanical effects, fos provide clinical benefits for individuals with cm. the objective of this rct will be to evaluate the effectiveness of medially wedged fos with a metatarsal pad in reducing pain and improving foot function in individuals with cm. the hypotheses of this rct will be that medially wedged fos with a metatarsal pad will significantly reduce pain and significantly improve foot function compared to sham fos. the study is a rct with a parallel-group design, conducted as a participant- and assessor-blinded superiority trial. in this trial, participants with cm will be allocated to either the intervention group (customized fos) or the control group (sham fos). participants will be recruited from the université du québec à trois-rivières (uqtr) outpatient podiatry clinic and via social media invitations. the participants will be randomized to one of two groups, each receiving a different model of fos (customized or sham). the total duration of participation is 4 to 5 months (from the first contact until the last data collection). the recruitment period planned for this study is from april 2025 to october 2026. participants will receive $25 after each follow-up (6 weeks and 12 weeks), so a total amount of $50. all included participants will be randomized into one of the two groups (intervention or control) using a minimization method (allocation ratio of 1:1) to ensure that both groups will be balanced with respect to predetermined criteria. these criteria have been identified based on factors known susceptible to influence the response to the treatment: gender, age and foot posture index (fpi). the findings from a recent study showed that metatarsalgia is most common in middle aged women (60%) with a neutral foot position (51%) and with an average age of 54 years. participants will be randomized using a computer-generated list of random numbers which will be placed into sealed and opaque envelopes numbered by an independent research assistant that is not involved in the selection, intervention, or assessment of participants. each envelope will be opened in front of the participants at the end of the baseline assessment by another independent research assistant. once the fos are manufactured, participants will return to uqtr to collect them. during this visit, participants will complete the initial questionnaires, and plantar pressure measurements will be taken with and without fos. the plantar pressure will be collected with a pedar-x in-shoe pressure measurement system (novel corporation, munich, germany), sampling at 100 hz. the insoles of this system will be inserted between the foot and either the insole of the shoe or the fos. once participants are equipped with the plantar pressure system, the participants will be allowed five minutes of acclimatization. then, participants will walk 10 times at a self-selected speed on a 10-meter walkway. the second and third assessments will be completed by phone or visioconference by a member of the research team, blinded to the group allocation of the participants. the investigators will use redcap (research electronic data capture) for randomization and the questionnaires. redcap is a secure, web-based software platform designed to support data capture for research studies, providing 1) an intuitive interface for validated data capture; 2) audit trails for tracking data manipulation and export procedures; 3) automated export procedures for seamless data downloads to common statistical packages; and 4) procedures for data integration and interoperability with external sources.

Eligibility criteria:
inclusion criteria: 1. are aged 18 years or over, 2. have bilateral or unilateral metatarsalgia under one or more of the lesser metatarsal heads for at least 3 months (pain score of ≥ 4 out of 10 on a visual analogue scale (vas)) that is aggravated by weight-bearing activities, 3. are able to walk without assistive devices (e.g., cane, walker), 4. are willing to wear shoes that will accommodate their fos on a daily basis and 5. are willing to minimize the use of other interventions (e.g., pain medications, physical therapy) during the trial period exclusion criteria: 1. have arthritis, 2. have neurological diseases (e.g., intermetatarsal neuroma) or other mechanical pain, plantar corns (e.g., intractable plantar keratoma), 3. have a history of orthopedic foot surgery, 4. have prior use of customized fos, 5. have cognitive impairments, 6. are pregnant.

Keywords: rct metatarsalgia foot orthoses sham customized